Ruggedized electrical connecting lead

ABSTRACT

IN AN ELECTRON TUBE SUCH AS A VIDICON, CONDUCTOR READS ARE USED TO CONNECT VARIOUS ELECTRODES IN THE TUBE TO EXTERNAL TERMINALS. SOME OF THE LEADS ARE OF A CONSIDERABLE LENGTH IN THAT THEY CONNECT TO ELECTRODES WHICH ARE LOCATED AT AN END OPPOSITE TO THAT OF THE TERMINALS. THESE LEADS ARE EMBBEDED IN INTERNAL GROOVES IN THE GLASS ENVELOPE   WALL AND FRITTED OVER WITH SOLDER GLASS. THE EMBEDDED LEADS PROVIDE SECURE CONNECTIONS AND RUGGEDIZE THE TUBE ASSEMBLY TO BETTWER WITHSTAND SEVERE SHOCK AND VIBRATIONS.

United States Patent Filed Dec. 21, 1970, Ser. No. 100,072

Int. Cl. H01j 5/00 US. Cl. 313-317 7 Claims ABSTRACT OF THE DISCLOSURE In an electron tube such as a vidicon, conductor leads are used to connect various electrodes in the tube to external terminals. Some of the leads are of a considerable length in that they connect to electrodes which are located at an end opposite to that of the terminals. These leads are embedded in internal grooves in the glass envelope wall and fritted over with solder glass. The embedded leads provide secure connections and ruggedize the tube assembly to better withstand severe shock and vibrations.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to electrical connecting lead devices, and more particularly to a ruggedized lead connection structure embedded in a wall of vitreous material to withstand severe shocks and vibrations.

Description of the prior art Electron tubes of the vidicon type usually include an evacuated glass envelope having a base with terminal connections and a cathode electron beam gun at one end, a photo-conductive target faceplate and output connections at the other end, and beam scanning means, and a number of accelerating electrodes positioned along the tube intermediate the cathode and faceplate for directing the electron beam onto the faceplate. An example of such a tube structure is found in US. Pat. No. 3,391,297, issued July 2, 1968. Certain of the electrodes, particularly a mesh grid, are disposed adjacent the faceplate remote from the terminal end and are usually connected to one of the ter minals via a relatively loose internal insulated wire adjacent the envelope wall along the length of the tube. However, it has been found that these leads are subject to breakage or become disconnected at the joints between the leads and connections to the electrodes, particularly when the tube assembly is subjected to shock and vibration, such as when mounted in a satellite, airplane or missile. It has been found that despite the use of rather elaborate securing devices the aforementioned problem of disconnecting joints has been difiicult to rectify.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved more rugged electrical connecting lead structure and a more secure connection for conductor leads in an electron tube assembly.

These and other objects of the present invention are achieved in accordance with the present invention by embedding a longitudinal connecting lead within the in ternal glass wall of the tube envelope, preferably by plac ing the lead in a corresponding groove in the Wall and fritting over the lead with vitreous solder glass. In addition, an accelerating electrode in the form of an internal annu lar conductive wall coating may be deposited on the glass directly over the embedded connecting lead. The external connections to the leads are made through terminals in a common base.

The aforementioned and other objects and features of the present invention will become more apparent when considered with the following detailed description of the preferred embodiments in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cross-sectional and longitudinal view of a vidicon tube embodying the present invention; and

FIG. 2 is a partial cross-sectional view substantially in the plane 2-2 of FIG. 1 showing a groove and a connecting lead fritted in the groove according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, as shown in FIG. 1, a vidicon tube of a generally conventional design includes an evacuated elongated glass tubular envelope 10 with a photoconductive faceplate 12 mounted at one end and an electron beam gun including a cathode 14, control grid 16 and accelerating electrode 17 mounted at the other end thereof, with a suitable magnetic deflection yoke disposed around the electron tube for deflecting electron beams from the cathode across the photo-conductive faceplate. The tube includes several intermediate electrodes for forming, focusing and accelerating the electron beam, such as an annular drift tube electrode 18 coated on the internal Wall surface of the envelope, which also aids in eliminating noise introduced by stray electrons, and a mesh grid 20 positioned at the end parallel to and adjacent the photoconductive faceplate 12.

As one of the novel features, most of the power connections and necessary D.C. voltages are applied through terminals 21, 22, 23, 24 and 25 disposed through the end wall or base of the tube opposite the photo-conductive faceplate, and internal conductor leads 31, 28, 29, 30 and 27 connect the terminals to cathode 14, grid 16 and electrodes 17, 18 and 20, respectively.

The photoconductive faceplate itself typically includes a radiation transmissive layer 32, which may be a part of the glass envelope or a separate glass or quartz plate, an electrically conductive radiation transmissive layer 34 coated on the transmissive layer 32 and a photo-conductive layer 36. The conductivity of the photo-conductive layer 36 varies in accordance with the intensity of the radiation image impinging thereon and the scanning electron beam 38 from the cathode provides a read-out signal of this variation. The output signal is taken out through lead 40 and coupled to a suitable utilization means. Inasmuch as the operation of the vidicon of the aforedescribed type is generally known, no further description is necessary.

In accordance with the present invention the conductor lead 27 connecting the mesh grid 20 to the terminal 21 is embedded in the tubular wall of the vidicon tube, as more clearly shown in FIG. 2. Preferably a longitudinal groove 42 is formed in the internal side of the glass wall and then a conductive lead, preferably of high conductivity type such as platinum wire, is placed in the groove and fritted over with a suitable dielectric fritting compound such as vitreous solder glass, commercially marketed by Owens-Illinois Corporation under the designation 86-7. The frit preferably fills the groove over the wire to maintain a continuous smooth cylindrical internal surface for the glass tubular envelope. While the drawings show only one lead embedded in the glass wall, any number of leads may be similarly embedded and connected to other electrodes and terminals. It is important that, in fritting the glass groove, care must be taken to cover the lead adequately so that it will not during the manufacturing operation the conductive wall coating must be deposited over the surface area after completion of the glass fritting.

By embedding the leads in the glass wall in the manner described above, the leads are firmly secured to become an integral part of the internal tubular structure and accordingly are not subject to breakage or disconnection as in the case with loose leads extending within the tube in the conventional tubular structure. In addition, the provision of a common base for most of the terminal lead connections aids in simplifying and ruggedizing the tube.

As a suitable example, the present invention is illustrated in conjunction with a vidicon tube. But obviously the same structure could be readily applied in various other devices where embedding of a lead in a wall of vitreous material is desirable. Thus, numerous modifications may be made in the embodiment of the present invention described above without departing from the spirit and scope thereof as set forth in the appended claims.

What is claimed is:

1. A device for securing electrical connecting leads comprising:

an elongated evacuated tubular envelope of a vitreous dielectric material having a thin wall portion,

an electrode disposed adjacent one end of said envelope,

a conductor terminal adjacent the other end of said envelope,

a longitudinal groove in an internal surface of said wall portion, and

a conductor lead positioned in said groove and having one end connected to said electrode and the other end connected to said terminal, and a vitreous frit material enclosing and sealing said lead within said groove.

2. The device according to claim 1, wherein said tubular envelope vitreous material is glass and said vitreous frit material is of a solder glass.

3. A device according to claim 2, wherein said lead is a platinum wire.

4. The device according to claim 2, wherein said glass envelope has a cylindrical internal surface, and said frit material fills the groove over said lead to maintain a substantially continuous smooth cylindrical glass surface.

5. The device of claim 4, wherein said envelope includes an electron tube structure having an annular conductive wall coating electrode on said glass surface over said lead and groove.

6. The device of claim 5, wherein said electron tube structure includes a vidicon structure having a faceplate at said one end and a base at said other end, a plurality of terminal connections disposed through said base, a mesh grid electrode adjacent said one end, said lead being connected between said mesh grid and one of said terminal connections.

7. The device of claim 6, wherein a further lead is connected between said wall coating electrode and another one of said terminal connections.

References Cited UNITED STATES PATENTS 3,391,297 7/1968 Santilli 313-96 2,210,489 8/ 1940 Lemmens et al 3133 17 FOREIGN PATENTS 966,369 3/1950 France 174-5058 JOHN K. CORBIN, Primary Examiner T. H. KUSMER, Assistant Examiner US. Cl. X.R. 

